This San Francisco-based software development company is making a name for itself by improving the tools used for "version control"—the process by which all changes to a piece of computer code is logged and tracked. As any developer will tell you, one misplaced character can cause a program to crash.

GitHub makes it easier to see where everything is and who put it there. Any developer working on a piece of code has full access to it and can make improvements.

The company's version-control system was built around a piece of software created in 2005 by Linux developer Linus Torvalds that he named Git—a British slang word referring to a foolish person. In 2008, as Git adoption grew, developer Tom Preston-Werner (creator of the avatar service Gravatar) and several colleagues realized that a site that could run most Git functions was needed. They created and launched GitHub, a site that allows coders to collaborate over the Internet easily and in real time.

The company's growing influence caught the attention of venture capital firm Andreessen Horowitz, which invested $100 million in 2012. Today the company has more than 6 million users working on over 13 million projects in nearly every program language that exists.

On the company's disruptive impact:

"We’ve seen tremendous growth over the past two years, growing from 1 million people collaborating on 2 million software projects in 2012, to more than 6 million people collaborating on 13 million software projects currently."-Chris Wanstrath, co-founder and CEO